Scotland’s DNA: In search of our roots

Author and historian Alistair Moffat is leading a groundbreaking plan to test the DNA of thousands of Scots. The project, never attempted before, is launched today in The Scotsman as part of a series on the origins of our nation

INSIDE all of us lies a hidden history, the story of an immense journey told by our DNA. Deoxyribonucleic acid is the molecule at the heart of the reproduction of all plants and animals. And since the discovery of its structure in 1953, scientists have been analysing our DNA to piece together the epic narrative of how human beings populated our planet.

DNA is inherited from our parents. Each of us has six billion “letters” of DNA – three billion from our fathers and three billion from our mothers. The letters are passed on in a certain sequence, but when mistakes in genetic copying occur over time, these changes or “mutations” are labelled markers. And they too are then passed on. Human DNA is very homogenous (and 95 per cent of our DNA is identical to that of chimpanzees) and these mutations or markers are tiny, but their identification does allow population movement in history to be much more clearly understood than it was.

Today is the beginning of a process where I hope thousands of ordinary Scots will come forward to have their DNA tested. It does not matter whether you have been in Scotland for one week or your family has lived here for centuries – the testing process can reveal fascinating data. From a simple saliva sample our scientists can trace your ancestry over many thousands of years and through new and developing technology, we can answer a fundamental question – where do we come from?

I hope that 20,000 Scots will come forward to be tested to answer questions such as: Are you a Pict? Are you a Viking? Or even a descendent of Genghis Khan.

As far as we know this is a unique project. No other country in the world has ever done this. And thanks to modern technology we have the ability to discover who we are and where we came from.

By having your DNA analysed you become part of the sweep of this huge story. Your origins, your ancestors, the people who made you will emerge from the shadows as our research reaches back into the darkness of the deep past – your past. One continent unites us all, though – Africa. All human beings are descended from Africans. In 70,000BC the Indonesian volcano known as Mount Toba blew itself apart in a super-colossal eruption that almost ended life on Earth. As millions of tons of tephra, pumice and ash rocketed into the atmosphere and dense black clouds blocked the sun for several years, plants withered and the animals and people who depended on them died.

Geography saved us from extinction. In the steep-sided rift valleys of Eastern Africa a remnant of perhaps only 5,000 human beings survived the nuclear horrors of the eruption. All of us are their descendants.

Soon after the cataclysm of Toba, as the planet began to recover, a tiny group of only three or four hundred left the sanctuary of the rift valleys and walked northwards. When they reached the Horn of Africa, modern Djibouti, they crossed the Red Sea to the Arabian peninsula. From there these pioneers walked into empty landscapes, forded great rivers and braved endless new horizons, and eventually their descendants populated the whole of the rest of the world.This is the journey of all of us, with its twists, turns, pauses, advances and retreats that our DNA allows us to trace, the great journey out of Africa to Scotland.

And so all Scots are immigrants. As a nation at the farthest reach of Europe, our origins are diverse, unexpected and fascinating. By taking a simple DNA test, you will also become part of a great national project. By gathering large numbers of samples, all treated anonymously, we aim to answer another fundamental question – who are the Scots?

How is it possible to retrace the steps of our ancestors by analysing the DNA of living people? Inheritance is the key. Each of us inherits around 6 billion letters of DNA from our parents, 3 billion from each. Made up from four chemicals – adenine, cytosine, guanine and thymine – our genes are read by scientists like very long strings of letters, sequences of A,C,G and T.

There are two special sorts of DNA. Our fathers pass on Y chromosome DNA to their sons, while mothers pass on mitochondrial DNA, or mtDNA, to their sons and to their daughters. But mtDNA dies with men and it survives only in the female line. When people are tested, that means men carry two stories inside them; a Y chromosome lineage and their mtDNA lineage. Women have only one; an mtDNA story.

When human beings walked up the empty river valleys of Europe and sailed along its uninhabited coastlines to reach Scotland, they did not stay long. The last Ice Age was beginning. As storms blew over northern Europe and ice and snow blanketed the land, people fled south and all life in the frozen landscape was erased. In 1994 a miraculous survival was discovered. At Chauvet in south-west France archaeologists found a cave, what was known as an ice-age refuge, full of beautiful paintings of animals – herds of wild cattle, deer, horses, bison and their predators, lions, bears – and men. On the soft clay floor of Chauvet they noticed the footprints of a little boy. Scorch-marks and muddy hand-prints showed that he had carried a torch into the darkness. He was the last person to see the magical paintings before the cave was lost to history for 27,000 years. The little boy is one of our earliest known ancestors and he has 100,000 direct male descendants living in Scotland now.

How is it possible to know this? As DNA research intensified, scientists noticed occasional tiny errors of copying as our 6 billion letters were passed on down the generations. Known as markers, they were found to originate in particular parts of the world and through a measurement called the molecular clock, they could be dated. The little boy in the French cave carried a marker labelled M284 and 4 per cent of all Scottish men have inherited it.

As the ice began to melt in the centuries after 11,000BC, pioneers left the refuges and walked northwards. In a very short time they reached what was then the farthest north-western peninsula of Europe and M284 became one of the founding lineages of Scotland.

Many waves of immigration followed, right up to recent times, and Scotland is now a nation of men and women of tremendously diverse origins. This richness can be measured by DNA testing and using an aggregate of many individual stories, a genetic map of Scotland can at last be drawn. And finally, with your help, two central questions can be answered; where do we all come from and who are we?

PROFILE

• Born in Kelso in 1950, Alistair Moffat graduated from the University of St Andrews in 1972 and has also degrees from the University of Edinburgh and the University of London.

• In 1976 he became director of the Edinburgh Festival Fringe where he stayed for five years before moving to STV where he won a BAFTA for his documentary on the Lockerbie bombings.

• Moffat, left, has written over 20 books, several of which have been made into television series. These include Tyneside, The Reivers and The Wall.

• He founded the Borders and Lennoxlove Book Festivals and served as their director. He has also been involved with Scottish national literacy initiative Book Nation.

• Moffat was elected Rector of the University of St Andrews on 28 October, 2011, which is a three-year post that has previously been held by JM Barrie, Rudyard Kipling and John Cleese.